AC 2008-240: USING LOGIC CONTROL IN A SAFETY AND FIRE PROGRAMFIRE ALARM SYSTEM ENGINEERING COURSE

Harry Franz, University of Houston-DowntownProf. Harry Franz is an Associate Professor in the Control & Instrument Electronics DesignProgram and Safety & Fire Program at the University of Houston Downtown (UHD) in Houston,Texas. He has a BSEE and MSEE from the University of Pittsburgh. He holds a current P.E. andis a member of the NSPE and TSPE. He has worked in industry for sixteen years. He is a memberof the IEEE and advisor to the UHD IEEE Student Organization. He is also a member the ASEEand ISA. He has been very active in the Tau-Alpha-Pi national ET honor society.

© American Society for Engineering Education, 2008

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Using Logic Control in a Safety and Fire Program

Fire Alarm System Engineering Course

Abstract

The purpose of this paper is to describe the use of programmable logic controllers in a Safety and

Fire program Fire Alarm System Engineering course (ENGR-1403) of a four-year university.

The students in the course accomplish programmable logic control by using Automation Direct

programmable logic controllers. The students achieve knowledge of generic logic control

through the use of ladder logic, logic statements, and functional block diagram programming

techniques. The students use a variety of software in the course that includes circuit software and

LabVIEW. The LabVIEW software is used for both the design and simulation of fire alarm

logic systems. In addition, the students use Honeywell commercial fire alarm control processors

to perform practical system setup programming for vendor specific applications. The focus of

this paper is on the programmable logic control teaching techniques that are used in the ENGR-

1403 course and the respective student exercise and project work

The students in the ENGR-1403 course have various levels of experience and academic

backgrounds. Students in the course often have experience in the installation or maintenance of

fire alarm systems. Typically the preponderance of the class students does not have a significant

amount of experience using programmable logic. While some students may have limited

programmable logic experience, their course entry experience most usually is not enough to

allow them to program more advanced exercises or projects.

Discussed in this paper are the learning strategies and teaching methods that are used to impart

knowledge of programmable logic control to the fire alarm systems engineering course students.

First the fundamentals of basic logic are given in the course with special applications to fire

alarm systems. Next, programmable logic methods are put forth. Ladder logic is then given and

the respective mnemonic statements for the ladder logic are presented. Finally, functional block

diagram logic programming is given. At all stages of learning relevant applications to fire alarm

system are used.

Strategies that are used in the course to increase the student knowledge of fire alarm logic are

taken from both engineering courses and from industrial training courses. Most of the class

students have not taken a digital logic course. Therefore, logic gates, truth tables, Venn

diagrams, and logic statements that are typically found in digital logic courses are presented in

the fire alarm systems class. In addition, hands-on and industrial training methods are used. It is

allowed for students to help each other perform exercises, but more often than not, few students

in the fire alarm systems engineering class initially have enough prior knowledge of

programmable logic to help the others. As the course progresses, however, students that advance

more rapidly help support the others. Finally, it is very important to note that the knowledge of

programmable logic control gained in the fire alarm system class is a very valuable asset for

students when they become employed in fire and safety or in many other areas of industry.

Student exercises and group projects will be given that use programmable logic control.

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Introduction

The goal of the ENGR-1403 course is to have the students gain both theory and application.

First, basic theory is completed that includes logic symbols, logic gates, truth-tables, logic

statements, logic manipulation, and basic combinational logic examples. The next approach used

is to impart knowledge of the application of logic control. This is done in a manner to allow a

student to use, understand, and even design a fire alarm system control unit. This is

accomplished by having the students learn and use the more general logic software packages first

and then learn the programmable logic software. The understanding of logic programming

enables the ENGR-1403 students to design systems in addition to performing the application of a

preprogrammed and pre-engineered fire alarm signaling control systems.

The students learn logic theory through the use of educational software that includes LabVIEW.

Because the students that enroll in the ENGR-1403 class are not required to have a previous

knowledge of the LabVIEW software, the basics of LabVIEW are taught within the ENRG-1403

course. Fundamentals of LabVIEW and examples are given in both the classroom and lab.

The ENGR-1403 students are also not required to have previous knowledge of programmable

logic and software. The students learn programmable logic controller software and hardware

applications through the use of programmable logic controllers that are in the ENGR-1403

course lab. Note that only smatterings of students in the ENGR-1403 course, mainly those that

work in industry, do have some limited experience with programmable logic.

A fire alarm system systems laboratory is used in the ENGR-1403 course with the lecture. This

fire alarm signaling systems laboratory has programmable logic controllers that allow fire

protection systems to be designed from scratch. This is in contrast to the mostly preprogrammed

commercial fire alarm signaling systems control panels that are also used in the ENGR-1403 lab.

The use of the ENGR-1403 lab programmable logic controllers also acquaints students with

programmable logic control which is an important tool that is used in industry. The students first

learn to program logic by using functional blocks and logic diagrams in LabVIEW. The students

then use the lab logic controllers to program mnemonics and logic diagrams for fire alarm

systems.

Background

The ENGR-1403 course of the Engineering Technology department contains the design,

installation, maintenance, and utilization of fire appliance and pre-engineered systems.

The course also contains the operational capabilities and utilization requirements of the fire

detection and signaling systems. In addition, the course contains demonstrations and computer

simulation of hazardous detection systems.

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Background (continued)

As mentioned previously the ENGR-1403 students are not required have prerequisite knowledge

of LabVIEW. The rational for the use of LabVIEW rather than Visual Basic software in the

ENGR- 1403 class is that most students find LabVIEW easier to use to create logic control

panels for systems in a more direct and faster way than by using the Visual Basic software.

Even students that have much experience with Visual Basic software most often prefer to use

LabVIEW rather Visual Basic to make control panels and logic diagrams for the fire alarm

signaling systems. The functional block programming of the LabVIEW software is also most

often preferred by the ENGR-1403 students rather the use of the use of mnemonics.

As mentioned previously the ENGR-1403 students are also not required to have prerequisite

knowledge of programmable logic. The Automation Direct logic units and software are used in

the ENGR-1403 course because they are easy to learn to program and can be used for various

applications. The Automation Direct industrial software is designed to create logic diagrams

either directly or by using standard logic mnemonics that are used in industry. That is the

Automation Direct software allows the students to learn the use of a tool that is required by

industry.

Methodology

The ENGR-1403 course students are required to work individually on the basic exercises, but

work in groups on the projects that are relatively large. Both the LabVIEW software and

Automation Direct software packages are available on the fire alarm signaling lab computers.

The Automation Direct software is also available in the form of mnemonics on the lab logic

controller hardware units. The hardware units in the fire alarm signaling labs vary from logic

controller “bricks” which are single self-contained smaller units to larger logic controllers with

modules. Student versions of the LabVIEW software are also available in the university

bookstore.

To acquaint students with the basic fire alarm logic software, lectures are given in the course on

logic control using LabVIEW and Automation Direct software. Examples and demonstrations

are given in the lab. The students work along with the instructor and then work independently. In

addition, professional training methods are used in the course. These methods use a varied set of

lectures, demos, labs, and student group action to keep the course moving and interesting. As the

level of work progresses students are then assigned to work in groups rather than individually for

the more complex larger projects.

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Discussion of Student Work

As previously noted the students are required in the earlier part of the course to work

individually on exercises, but in the later part of the course work in groups on larger projects. .

The group size varies with the class size. Student group projects are discussed below and then

are shown in figures.

Fire Detection, Alarm, and Suppression System for an Industrial Gear Unit Factory Project

A student group programmable logic controller project assignment is shown in figure 1-A.

The actual student group work hardware board is shown in figure 1-B. The hardware board uses

an Automation Control “brick” logic controller for detection and notification for the factory fire

alarm system project. Note that the hardware board with the Automation Direct programmable

logic controller in figure 1-B is a “brick” logic controller shown with input, output, and wiring.

The gear factory has initiating device detectors for fire signatures that include smoke, high-heat,

chemicals, and flames that use a UV detector. The factory has notification appliances that

include horns and sirens for local alarms, general alarms, and evacuation alarms. The logic is

performed by the controller program created by the students for inputs, logic, timing, outputs,

and other functions. The program made by the students uses mnemonic statements.

Fire Detection, Alarm and Evacuation System for Office Building Project

A student group LabVIEW project is shown in figure 2-A. This project has been made by the

students using LabView. The view shown is the front panel view.

The evacuation system directs occupants to the nearest exit away from the fire, not to the nearest

exit which may be the location of the fire or close to the fire. Fire signature detectors are shown

with notification appliances that include directional guide arrows to direct occupants away from

the fire to the nearest exit. The students have programmed the logic using function blocks.

Note that this evacuation project also has served as a guide for a hardware board. The hardware

board created later uses a programmable logic controller and other hardware for a larger more

sophisticated evacuation system. A sample of the programmable logic controller logic

mnemonics used for the hardware board is given in figure 2-B.

Fire Detection, Alarm and Evacuation System for Two-room Building Project

A student group LabVIEW project with combined analog and digital functions is shown in

figure 3-A the front panel view and in figure 3-B the functional block diagram view. Logic

equations are shown in figure 3-C. The high-heat detection system compares analog data

supplied by each of the thermometers to the respective set point for each room. If either room has

a high temperature then both of the alarms will notify. The suppression will activate only for the

respective room with the high temperature.

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Examples of Student Work

Figure 1-A

Student Assignment

Fire Detection, Alarm, and Suppression System for an Industrial Gear Unit Factory Project

EVACUATE ALARM # 6

GENERAL ALERT ALARM # 5

LOCAL ALARMS

At each unit

detect#4-a detect detect#4-b detect detect-c detect#7

high-heat smoke high-heat smoke high-heat smoke

detect#1 detect#2 detect#3

chemicals high-heat UV

Figure 1-B

gear

unit

J GEAR ASSEMBLY LINE

O

O

METAL RING TEETH HOUSING

AREA AREA AREA AREA

ALARM #1 ALARM #2 ALARM #3 ALARM #4

LOCAL ALARM FOR AREA ONLY IF SMOKE

LOCAL ALARMS FOR AREA AND ADJACENT AREA IF HIGH-HEAT

LOCAL ALARMS FOR AREA AND ADJACENT AREA IF CHEMICALS

GENERAL ALERT ALARM IF TWO AREAS DETECT (ANYTHING)

EVACUATE ALARM FOR UV, or if MORE THAN TWO AREAS DETECT

ACTIVATE / RESET BUTTON FOR SYSTEM

SUPPRESSION UNIT

ACTIVATES LOCALLY

with LOCAL ALARM.

SUPPRESSION UNITS

ACTIVATE and

LATCH-IN with

GENERAL ALARM

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Examples of Student Work (continued)

Figure 1-B Student Work Hardware Board with Logic Controller

Fire Detection, Alarm, and Suppression System for an Industrial Gear Unit Factory Hardware

“Brick” Logic Controller

for above

Hardware Board

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Examples of Student Work (continued)

Figure 2-A Student LabVIEW Project Work Panel View

Fire Detection, Alarm, and Evacuation System for an Office Building Project

Figure 2-B Programmable Logic Controller Logic Mnemonics

STR X4 OR X7 STRN X1 ANDSTR

OR X5 OR X10 ANDN X2 OUT Y1

OR X6 ANDN X3 (where N≡ NOT)

EVACUATION SYSTEM

Directs evacuation by using arrows

to direct evacuees to the nearest exit

away from the fire

EXIT

EXIT

EXIT

EXIT

Smoke is

detected

in this corridor

Smoke

detector

activated

directional

guide arrow

x 10

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Examples of Student Work (continued)

Figure 3-A

Student LabVIEW Project Work Front Panel View

Fire Detection, Alarm, and Evacuation System for a Two-room Building

One room is used as a store for sales and the other room is used as an office

for

STORE for

OFFICE

Suppression is

activated for office

Notification

alarm is

activated

Notification

alarm is

activated

Temperature

detected is

higher than

set point

Suppression is not

activated for store

Temperature

detected is

lower than

set point

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Examples of Student Work (continued)

Figure 3-B

Student LabVIEW Project Work Functional Block Diagram View

Fire Detection, Alarm, and Evacuation System for a Two-room Building

Figure 3-C Logic Equations for above Functional Bock Diagram

IF Thermometer G.T. Slide � Office Suppression ( where G.T. ≡ greater than )

IF Thermometer 2 G.T. Slide 2 � Store Suppression

( IF Thermometer G.T. Slide) OR (IF Thermometer 2 G.T. Slide 2 � Alarm Office

( IF Thermometer G.T. Slide) OR (IF Thermometer 2 G.T. Slide 2 � Alarm Store

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Student Work Feedback

The students have reacted to the use of logic control in the ENGR-1403 course in more than one

positive way. Note that the course students in the ENGR-1403 class are typically either

firefighters or non-fire fighter students that are taking the course as an elective for a program

other than safety and fire.

First, for reference the students especially fire fighters have been very interested to learn the

aspects of the National Fire Alarm Code, NFPA 72, and how to apply the Honeywell commercial

alarm control box and addressable alarm control box to various fire alarm systems. The

firefighter students in the course have stated that the knowledge of the Honeywell fire alarm

system control boxes makes them a better informed firefighter and a more aware firefighter. In

addition, practically all of the ENGR-1403 course students stated it was a valuable experience to

be able work on the design and installation of actual commercial fire alarm signaling systems.

Second, for the focus of this paper most of the students including those that are fire fighters have

stated that they have been very grateful to learn the aspects of applying programmable logic

control to the subject area of fire alarm system design. In addition, most of the students have

stated that the knowledge of programmable logic is a very useful and vital tool for the

understanding and design of fire alarm control systems as well as a vital tool for industry in

general.

Summary and Conclusions

The students in the ENGR-1403 Fire Alarm Signaling course benefit from the use of both the

LabVIEW and Automation Direct software. The ENGR-1403 course projects require knowledge

of fire alarm signaling systems and knowledge of programming. Knowledge of programming by

function blocks using the LabVIEW software and knowledge of programming logic controllers

in mnemonics or logic diagrams are given in the course. It is important to note again that the

Automation Direct Logic Controllers are actual units used in industry and the use of these

controllers is a valuable learning experience for the ENGR-1403 students.

Bibliography:

1. UHD Undergraduate and Graduate Catalog 2007 / 2008 edition

2. UHD ENGR-1403 Students Projects

3. LabView 8 Student Edition National Instruments, Prentice Hall

4. Automation Direct Programmable Logic Control Manuals

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